This Valentines day evening I didn’t take my partner out, instead I was down at the local hospital for a endoscopy which is part of a new initiative to screen for bowel cancer which we get in the UK once we start becoming old and decrepit. What’s great is they allow you to watch it as it’s going along (although they did discourage me from filming it). What they are doing is hunting for cancers and polyps (which can grow into cancers) in the bowels. They will then remove any small ones and take biopsies. I was more than surprised that it actually looked rather beautiful up there. So much for asubha. 
Having grown up watching TV and gone through my fair share of crime and horror movies, I wonder if I’ve become immune to seeing asubha type images on screens? Bloated corpse? Plenty of those in CSI.
I retire from this conversation. I observe feeling understood, not understood, misunderstood, misrepresented, unable to connect due to conditioned reactions probably caused by my lack of skill or unconscious associations with casual vocabulary, frustration, acceptance.
I thank all participants for sharing, and hope no harm is done to any, but fruitful support of effective practice is the result for each especially myself.
edit: I am aware this post may be seen as passive aggressive. I do not intend that, but felt just walking away in silence would be p-a and would do at least minor harm. Doing my best, as I believe all do as a matter of practice.
Perhaps this is tangential but I think this may help me understand why 4 fold sangha! 
Please, enjoy excellent day or night, friends.
Based on my own experiences with asubha practice, I wouldnt easily suggest it in general . It is very powerful Indeed, but in my opinion not something one plays around with …
I think walking away in silence from a thread is a totally legitimate and reasonable option, and should not be interpreted as passive aggressive. There’s a number of skillful reasons to walk away, not least among them, we have so little time and energy (marana-s-sati), there are usually far more important things to do.
Hey Mat, thanks for posting this 
Question, it is my understanding, that in order to practice asubha, one first needs to have their mind concentrated as in perhaps one of the jhanas or at the very least access concentration (upacara).
Only then can one ‘bring up’ a mental image that represents the repulsiveness of the body?
Is my understanding correct? Always happy to learn from others.
Thanks in advance 
One of the first times I touched “asubha” I sat and watched my own hand - recollecting our life together and “falling in love” with my grasping tools … After about 5 minutes i tought about resting my eyes a bit, closed them and took 4 or 5 deep breaths, and at the end of the last breath a shiny nimitta “my beautiful hand” appeared with all it’s details and shining like a sun in the mind. It surprised my out of “samadhi”, but gave me a nice insight into how I could do it and how incredibly close it is all the time.
The best advice I’ve heard from a teacher regarding Jhanas and Nimittas, is: Jhana is a big toy, and Nimitta is a small toy …
Not at all. It is one of the ‘preparatory’ meditations for Mindfulness of breath, so it can be used right from the start. Since it is more discursive (I guess that would depend on how it is practiced as well), it is less calmer than Mindfulness of breath so more suited as a precursor when the mind is also more distracted. This is when it helps to reduce the hindrances especially sensual cravings. However as you say if the image is remembered and brought up in upacara (hindrance free) samadhi then it is particularly powerful- this method can take the meditator into jhana. But it helps to be able to go into jhana already, to facilitate this.
Take an image that is of manageable intensity of ‘asubha’ - don’t force yourself to do anything harder. Anatomy drawings are less intense but essentially something that is not too hard for the meditator - it’s personal. Practicing it little by little over time is better than all in one go.
Combining it metta, Buddhanussati to tackle the other types of the hindrances is helpful to ‘balance’ things out. In any one sitting if it gets to be too much just stop - no harm done.
The idea is to come to a place of understanding the reality of the body - not just the illusion of the skin and ideally not fall into aversion though this might occur occasionally it is temporary if practiced together with metta which will counteract it. Regardless I’m quite certain no one will be inclined to practice this. 
With metta
Thank you
Here’s some suttas on the topic:
At Savatthi. “Monks, any desire-passion with regard to the eye is a defilement of the mind. Any desire-passion with regard to the ear… the nose… the tongue… the body… the intellect is a defilement of the mind. When, with regard to these six bases, the defilements of awareness are abandoned, then the mind is inclined to renunciation. The mind fostered by renunciation feels malleable for the direct knowing of those qualities worth realizing.” SN27.1
Starving the Hindrances
"Now, what is lack of food for the arising of unarisen sensual desire, or for the growth & increase of sensual desire once it has arisen? There is the theme of unattractiveness [Asubha sanna] To foster appropriate attention to it: This is lack of food for the arising of unarisen sensual desire, or for the growth & increase of sensual desire once it has arisen. SN46.51
Asubha sanna includes a sense of the repulsive quality. Otherwise it won’t counteract very well, the sensual cravings towards the body.